implement lzss encoding

5 files changed, 180 insertions, 0 deletions

diff --git a/tests/tlzsschain.nim b/tests/tlzsschain.nim
new file mode 100644
index 0000000..241a0f1
--- /dev/null
+++ b/tests/tlzsschain.nim
@@ -0,0 +1,30 @@
+# gzip-like LZSS compressor
+# Copyright (C) 2018  Pacien TRAN-GIRARD
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import unittest
+import polyfill, lzssnode, lzsschain
+
+suite "lzsschain":
+  test "decode":
+    let chainArray = [
+      lzssCharacter(0), lzssCharacter(1), lzssCharacter(2),
+      lzssCharacter(3), lzssCharacter(4), lzssCharacter(5),
+      lzssReference(4, 6), lzssCharacter(0), lzssCharacter(1),
+      lzssReference(3, 8), lzssCharacter(5),
+      lzssReference(3, 3), lzssCharacter(5)]
+    var chain = lzssChain()
+    for node in chainArray: chain.append(node)
+    check chain.decode() == @[0'u8, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 4, 5, 0, 5, 5, 0, 5, 5]
diff --git a/tests/tlzssencoder.nim b/tests/tlzssencoder.nim
new file mode 100644
index 0000000..253d0ac
--- /dev/null
+++ b/tests/tlzssencoder.nim
@@ -0,0 +1,62 @@
+# gzip-like LZSS compressor
+# Copyright (C) 2018  Pacien TRAN-GIRARD
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import unittest, sequtils, lists, tables
+import matchtable, lzssnode, lzsschain, lzssencoder
+
+suite "lzssencoder":
+  test "commonPrefixLength":
+    check commonPrefixLength([], [], 0, 10) == 0
+    check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 0, 10) == 2
+    check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 1, 10) == 2
+    check commonPrefixLength([1'u8, 2, 3], [1'u8, 2, 4], 1, 10) == 2
+    check commonPrefixLength([1'u8, 2, 3, 4], [1'u8, 2, 3, 4], 1, 3) == 3
+
+  test "longestPrefix":
+    let buffer = [
+      0'u8, 1, 2, 9,
+      0, 1, 2, 3,
+      0, 1, 2,
+      0, 1, 2, 3, 4]
+    var candidatePos = initSinglyLinkedList[int]()
+    candidatePos.prepend(0)
+    candidatePos.prepend(4)
+    candidatePos.prepend(8)
+    let result = longestPrefix(candidatePos, buffer.toOpenArray(0, 10), buffer.toOpenArray(11, buffer.len - 1))
+    check result.pos == 4
+    check result.length == 4
+
+  test "addGroups":
+    let matchTable = initMatchTable(seq[uint8], int)
+    let buffer = toSeq(0'u8..10'u8)
+    matchTable.addGroups(buffer, 0, 1)
+    check matchTable.len == 0
+    matchTable.addGroups(buffer, 2, 9)
+    check matchTable.len == 5
+    check toSeq(matchTable.matchList(@[1'u8, 2, 3]).items).len == 0
+    check toSeq(matchTable.matchList(@[7'u8, 8, 9]).items).len == 0
+    check toSeq(matchTable.matchList(@[2'u8, 3, 4]).items) == @[2]
+    check toSeq(matchTable.matchList(@[4'u8, 5, 6]).items) == @[4]
+    check toSeq(matchTable.matchList(@[6'u8, 7, 8]).items) == @[6]
+
+  test "lzssEncode":
+    let buffer = [0'u8, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 4, 5, 0, 5, 5, 0, 5, 5]
+    check toSeq(lzssEncode(buffer).items) == @[
+      lzssCharacter(0), lzssCharacter(1), lzssCharacter(2),
+      lzssCharacter(3), lzssCharacter(4), lzssCharacter(5),
+      lzssReference(4, 6), lzssCharacter(0), lzssCharacter(1),
+      lzssReference(3, 8), lzssCharacter(5),
+      lzssReference(3, 3), lzssCharacter(5)]
diff --git a/tests/tlzssnode.nim b/tests/tlzssnode.nim
new file mode 100644
index 0000000..cb584ab
--- /dev/null
+++ b/tests/tlzssnode.nim
@@ -0,0 +1,26 @@
+# gzip-like LZSS compressor
+# Copyright (C) 2018  Pacien TRAN-GIRARD
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import unittest
+import lzssnode
+
+suite "lzssnode":
+  test "equality":
+    check lzssCharacter(1) == lzssCharacter(1)
+    check lzssCharacter(0) != lzssCharacter(1)
+    check lzssReference(0, 1) == lzssReference(0, 1)
+    check lzssReference(1, 0) != lzssReference(0, 1)
+    check lzssCharacter(0) != lzssReference(0, 1)
diff --git a/tests/tmatchtable.nim b/tests/tmatchtable.nim
new file mode 100644
index 0000000..4b21f1d
--- /dev/null
+++ b/tests/tmatchtable.nim
@@ -0,0 +1,35 @@
+# gzip-like LZSS compressor
+# Copyright (C) 2018  Pacien TRAN-GIRARD
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import unittest, lists, sequtils, tables
+import matchtable
+
+suite "matchtable":
+  test "matchList":
+    let matchTable = initMatchTable(seq[int], int)
+    check toSeq(matchTable.matchList(@[0, 1, 2]).items).len == 0
+
+  test "addMatch":
+    let matchTable = initMatchTable(seq[int], int)
+    matchTable.addMatch(@[0, 1, 2], 42)
+    matchTable.addMatch(@[2, 1, 0], 24)
+    check matchTable.len == 2
+    check toSeq(matchTable.matchList(@[0, 1, 2]).items) == @[42]
+    check toSeq(matchTable.matchList(@[2, 1, 0]).items) == @[24]
+    matchTable.addMatch(@[0, 1, 2], 1337)
+    check matchTable.len == 2
+    check toSeq(matchTable.matchList(@[0, 1, 2]).items) == @[1337, 42]
+    check toSeq(matchTable.matchList(@[2, 1, 0]).items) == @[24]
diff --git a/tests/tpolyfill.nim b/tests/tpolyfill.nim
new file mode 100644
index 0000000..b48eb77
--- /dev/null
+++ b/tests/tpolyfill.nim
@@ -0,0 +1,27 @@
+# gzip-like LZSS compressor
+# Copyright (C) 2018  Pacien TRAN-GIRARD
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import unittest, sugar, lists, tables
+import polyfill
+
+suite "polyfill":
+  test "SinglyLinkedList append":
+    const data = [1, 2, 3, 4, 5, 6]
+    var L: SinglyLinkedList[int]
+    for d in items(data): polyfill.prepend(L, d)
+    for d in items(data): polyfill.append(L, d)
+    check $L == "[6, 5, 4, 3, 2, 1, 1, 2, 3, 4, 5, 6]"
+    check 4 in L